The present invention relates to an adapter device which can be detachably attached to a camera lens and can apply a click feeling to an operator when a photographing magnification is set.
Conventionally, a macro lens which is capable of close-up photographing is known. This type of macro lens employs a stationary ring, a focus ring rotatably connected to the stationary ring, and a sliding ring in which a focus lens is held and movable along an optical axis of the focus lens. The focus ring and sliding ring are coupled by a helicoid construction for moving the sliding ring in the optical axis upon rotation of the focus ring.
In the conventional macro lens, a slip off phenomenon of the focus point occurs due to the slight rotation of a focus ring after an indication has been matched to a prescribed value of the photographing magnification scale by rotating the focus ring. As a result, it has been troublesome to adjust the magnification scale, and an adjusting error tends to occur. Once the adjusting error has occurred, a scattering of the photographing magnification happens in the case of clinical photographing, for example, photographing the front of a row of teeth in the mouth of human being. Accordingly, the precise comparison and/or judgment to the clinical photograph which is photographed by using the macro lens becomes difficult.
It should be noted that a camera lens, where a click stop mechanism is integrally installed into a lens body of the camera lens is known, thereby enabling a click stop in a prescribed magnification. However, the camera lens integrally equipped with the click stop mechanism is very expensive because of such exclusive use, is very troublesome in operation of setting the prescribed magnification, and is not suitable for so-called mass production.